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A curvature meter and cornea technology, applied in medical science, eye testing equipment, diagnosis, etc., can solve problems such as inability to form placido rings, inability to use them in surgery, and projection of placido rings on the surface of the cornea, so as to reduce intraoperative risks and save money. The effect of operation time
Pending Publication Date: 2019-05-17
PEKING UNIV THIRD HOSPITAL
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Problems solved by technology
[0006] (2) Direct light projection is used without lens focusing;
[0007] (3) In order to measure the curvature of the cornea at different depths, it needs to be rotated, resulting in a large volume of equipment;
[0009] (5) The incident distance (the distance from the placido disc to the cornea) is fixed and not adjustable;
[0010] (6) The angle of incidence is fixed and cannot be adjusted, and must be projected directly to the cornea;
[0011] Disadvantages of corneal topography: large volume; must sit for inspection, cannot be set in the operating room, so it cannot be used during surgery (it cannot be used after corneal suture during surgery)
[0015] (1) It does not have a light source, and can only reflect the light of the microscope to the surface of the cornea. The light intensity is small and the image is not clear
[0016] (2) Because of the use of reflected light, direct contact with the cornea is required during use, and it cannot be used in real time during surgery to monitor changes in corneal curvature, and can only be used after suturing
If there is no direct contact with the cornea, the reflected
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[0080] Example 1:
[0081] First, determine the degree of the convex lens as D=15 degrees. At this time, V is the image distance. When it is set to 15cm, L (object distance) should be 12cm according to formula ①.
[0082] If R' is set to 1.0cm, R is 0.8cm, V is 20cm, and L=10cm, then R' should be adjusted to 1.6cm to meet formula ②; and the adjusted distance L from the convex lens 4 to the placido disc 3 It should be 12cm, so the adjustable distance of the lens 4 is 2cm at this time.
Example Embodiment
[0083] Embodiment 2:
[0084] First, determine the degree of the convex lens as D=20 degrees. At this time, V is the image distance. When the minimum setting is 15cm, L (object distance) should be 7.5cm calculated according to formula ①.
[0085] If R' is set to 1.0cm, R is e0.5cm, V is 20cm, and L=6.7cm, then R' should be adjusted to 1.5cm to meet formula ②; The distance L should be 7.5cm, so the adjustable distance of the convex lens 4 is 0.5cm at this time.
Example Embodiment
[0086] Embodiment three:
[0087] First, determine the degree of the convex lens as D=25 degrees. At this time, V is the image distance. When the minimum setting is 15cm, L (object distance) should be 5.5cm calculated according to formula ①.
[0088] If R' is set to 1.0cm, R is 0.4cm, V20cm, L=5cm, then R' should be adjusted to = 1.6cm, in order to meet the formula ②; and the adjusted distance L from the convex lens 4 to the placido disc 3 should be is 5.5cm, so the adjustable distance of the convex lens 4 is 0.5cm.
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Abstract
A corneal curvature instrument includes a cylindrical housing for accommodating the following parts of the corneal curvature instrument, a light source fixed near one end of the cylindrical housing, aplacido disc arranged in front of the light source and used for converting light emitted by the light source into light beams distributed in a concentric circle pattern, and a lens disposed in frontof the placido disc and used for magnifying and projecting the light passing through the placido disc onto the corneal surface to image a placido ring. By utilizing a lens imaging principle, the placido disc is projected to the surface of the cornea, a complete placido ring is formed on the surface of the cornea, the placido disc is hung on one side of a microscope, the placido ring projected to the corneal surface can be observed in an observation field of the microscope, direct contact with an eyeball is avoided, and operation errors caused by corneal deformation caused by compression produced on the eyeball are prevented. The operation space is provided for the operation, the corneal curvature condition can be observed in real time in the suturing process, the tightness of a sutures canbe adjusted instantly, the operation time is saved, and the risk in the operation is reduced.
Description
technical field [0001] The invention relates to the technical field of keratometers, in particular to a keratometer. Background technique [0002] The cornea is an important structure of the eye imaging system, and changes in the curvature of the cornea can seriously affect vision. For corneal transplantation, surgery or trauma, etc., the cornea needs to be sutured, and the tightness of the suture will affect the curvature of the cornea, thereby affecting the vision of the patient. At present, it is not clear whether the suture tightness will change the corneal curvature during the suture process. Therefore, it often causes a large difference in the corneal curvature after suture. If the effect of suture tightness on corneal curvature can be determined and adjusted during surgery, it is very important to improve the visual quality of patients after surgery. [0003] At present, there are corneal topography and keratometer to measure the curvature of the cornea clinically. ...
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